Optimisation of Home eNodeBs ~ Management of Relays and Repeaters - PowerPoint PPT Presentation

FP7 ICT-SOCRATES Optimisation of Home eNodeBs ~ Management of Relays and Repeaters Ove Linnell Ericsson Research 2009-09-30

Optimisation of Home eNodeBs – Introduction  Extensive use of indoor solutions, e.g. HeNBs, foreseen Up to 70% of the traffic load is indoor  Used to improve or create coverage and/or capacity in small areas  Support open and closed subscriber groups  Minimal human intervention  Self-optimisation needed  Two use cases are studied: – Home eNodeB Handover Optimisation – Decide if handover should take place – Optimise handover parameters – Home eNodeB Interference and Coverage Optimisation – Optimise the coverage area while minimising interference WWW.FP7-SOCRATES.EU

Optimisation of Home eNodeBs – Control Parameters and Operator Policy Prioritized Control parameters  For interference and coverage optimization  For handover optimization – Maximum HeNB power – Hysteresis – Reference signal power – Cell Offset – Maximum UE power – D esired received power in HeNB (P 0 ) Operators may have different marketing priorities and performance targets that should be reflected in the self-optimisation. Attributes proposed for prioritisation:  Accessibility (e.g. call setup success ratio)  Retainability (e.g. call dropping ratio)  Quality (e.g. user throughput)  Coverage  Other possible requirements – Limit on change in macro performance – Ability to over-ride the self-optimisation Utility function proposed WWW.FP7-SOCRATES.EU

Optimisation of Home eNodeBs – Assessment Criteria  Need for metrics and methods to assess the gain of self-optimisation HeNB objectives:  High throughput for data  Satisfactory speech quality for voice  Avoid blocked/dropped calls  Minimise negative impact of HeNB on macro network  Overall metric based on comparison between HeNB with self-organisation and a reference case Weighted sum of Weighted sum of Overall metric for Capacity metric various blocking and assessment of various QoS metrics Coverage metric dropping metrics algorithm X (Alg_X) Reference value for Reference value for coverage capacity WWW.FP7-SOCRATES.EU

Optimisation of Home eNodeBs – Simulations Prioritized scenarios  For handover optimization  For interference and coverage optimization – Closed Access HeNBs – Open/Closed Access HeNBs – Varying eNB-HeNB distance – Varying UE speed – Varying HeNB signal strength relative – Hexagonal scenario, one area with to eNB strength houses and HeNBs – Varying load – Varying service type – Simplified test scenario: HeNB UE mobility WWW.FP7-SOCRATES.EU

Optimisation of Home eNodeBs – HO Simulations  Best server is determined based purely on received signal strength  Illustration of coverage of HeNBs (one color per HeNB)  Using 3GPP HO model Macro Back to macro Femto Another femto Pilot SINR (dB) Serving cell Femto Macro Back to macro WWW.FP7-SOCRATES.EU

Optimisation of Home eNodeBs – ICO Simulations  7 sites with 21 cells, one area with a grid of houses and HeNBs  HeNB placement varies within the house  Requested DL bitrate 1 Mbps Maximum Gain  Impact of varying HeNB DL power, DL Throughput P max = 200 mW P max = 80 mW Mbps WWW.FP7-SOCRATES.EU

Management of Relays and Repeaters – Introduction I (II)  Relays and repeaters are used to increase coverage and/or capacity of a eNodeB  Repeaters receive and amplify the received signal, including received interference.  Relays receive the actual data and then retransmit it WWW.FP7-SOCRATES.EU

Management of Relays and Repeaters – Introduction II (II)  A new relay/repeater needs to be connected to the network and to be configured  In some situations, the relay/repeater may disturb the network without improving coverage/capacity  The following areas have been identified as suitable for self-organisation; – Selecting locations for Relays and Repeaters – Automatic generation of configuration parameters – Interference coordination – Self-healing aspects – Load balancing aspects – Handover aspects  For now, the MRR work in SOCRATES has been put on hold due to lack of resources and status in standardization WWW.FP7-SOCRATES.EU

Management of Relays and Repeaters – Background and Objectives I  Intelligently Selecting Locations for Relays and Repeaters – Avoid time-consuming and costly measurements and/or usage of prediction tools – Automatically identify areas with no coverage or low performance – Generate proposals of repeater and relay positions in order to improve coverage and/or performance  Automatic Generation of Configuration Parameters – For repeaters a strong deviation of parameters from mother eNodeB applies – For relays some parameters are to be set up by default values, others are to be deviated from settings of mother eNodeB  Interference coordination – The introduction of relays and repeaters introduces new interference scenarios, which are significantly different to conventional macro cell networks. – Manage interference so that both macro and relaying links provide satisfactory throughput and latency  Self-healing – Detection of outages of relays / repeaters – Compensation of outages using relays / repeaters WWW.FP7-SOCRATES.EU

Management of Relays and Repeaters – Background and Objectives II  Resource Sharing – Relays and Repeaters provide connection for UEs with at least two hops on radio interface, resources can be shared in time and frequency domain – Optimisation of resources used in links to/from repeater with regards to – Throughput – Interference  Load balancing aspects – Additional load on backhaul link (eNB – RN) should be considered in load balancing problems – Load balancing between eNB direct user links and backhaul links of the RNs  Handover aspects – With Relays and Repeaters, handover settings should be adjusted for handover between – Macro to macro – Macro to relay – Relay to macro – Relay to relay WWW.FP7-SOCRATES.EU